<!DOCTYPE html>
<html>
<head>
	<title>js-output</title>
	<meta charset="utf-8">
	<script type="text/javascript">
		document.write('helloworld!');
		var date = new Date();
		document.write(date.toString());
		window.onload=function(){
			document.getElementById("demo").innerHTML = "新增加的内容";
			// document.getElementById("demo").innerHTML
		}
	</script>
</head>
<body>
	<h1>my first web page<h1>
	<p id="demo">original content!</p>
</body>
</html>